Beveling apparatus

Abstract

Apparatus for quickly and efficiently beveling the edges of a workpiece such as a sheet of glass having at least two pairs of parallel sides, generally a square, without manual intervention during the process. The workpiece is positioned on a conveyor with the first pair of parallel sides parallel to the direction in which the conveyor moves the workpiece. Guides are provided for maintaining the angular orientation of the workpiece. The workpiece is conveyed sequentially through: a first grinding apparatus which grinds the first pair of parallel edges; a first turntable which rotates the workpiece through a precisely controlled angle to position the second pair of sides parallel to the direction of transport; a second grinding apparatus which grinds the second pair of parallel edges; a first polishing station which polishes the second pair of edges; a second turntable which rotates the workpiece through a precisely controlled angle so that the first pair of edges is again parallel to the direction of transport; and a second polishing station which polishes the first pair of edges. Coolants, lubricants, and polish are sprayed on the workpiece as necessary. The position of the grinders and polishers with respect to the conveyor are adjustable such that the angle and depth at which the workpiece edges are ground and polished can be selected. In addition, these adjustments permit compensation for wear of the grinding wheels and polishing wheels. The polishers further include ammeters connected to their motors which indirectly measure the pressure exerted on the workpiece by the polishing wheel. The turntables are pneumatically operated so as to lift the workpiece from the conveyor, rotate the workpiece through a precisely controllable angle, and return the workpiece to the conveyor in a short period of time. Other configurations of grinders, polishers, and turntables are also contemplated.

We claim: 
     
       1. An apparatus for grinding the edges of a workpiece having at least two pairs of parallel sides comprising: a conveyor for transporting the workpiece through a series of sequential work stations;   first work station means for grinding the edges of a first pair of parallel sides of the workpiece when positioned parallel to the direction in which the workpiece is transported;   first means for lifting the workpiece from the conveyor, rotating the workpiece to position a second pair of parallel sides in a direction parallel to the direction in which the workpiece is transported, and lowering the workpiece back down to the conveyor;   second work station means for grinding the edges of the second pair of parallel sides;   third work station means for polishing the edges of the second pair of parallel sides;   second means for lifting the workpiece from the conveyor, rotating the workpiece to position the first pair of parallel sides in a direction parallel to the direction in which the workpiece is transported, and lowering the workpiece back down to the conveyor; and   fourth work station means for polishing the edges of the first pair of parallel sides.   
     
     
       2. An apparatus for beveling the edges of a workpiece having at least two pairs of parallel edges comprising: a conveyor for transporting the workpiece through the apparatus;   first grinding means for grinding the first pair of parallel edges of the workpiece, said grinding means including an adjustable positioning means for controlling the angle at which the grinding means grinds the workpiece, the depth to which the grinding means grinds the workpiece, and the distance of the grinding means from the conveyor;   first polishing means for polishing the first pair of parallel edges of the workpiece, said polishing means including an adjustable positioning means for controlling the angle at which the polishing means polishes the workpiece and the distance of the polishing means from the conveyor;   a turntable for rotating the workpiece about a vertical axis;   second grinding means for grinding the second pair of parallel edges of the workpiece, said grinding means including an adjustable positioning means for controlling the angle at which the grinding means grinds the workpiece, the depth to which the grinding means grinds the workpiece, and the distance of the grinding means from the conveyor; and   second polishing means for polishing the second pair of parallel edges of the workpiece, said polishing means including an adjustable positioning means for controlling the angle at which the polishing means polishes the workpiece and the distance of the polishing means from the conveyor.   
     
     
       3. The apparatus of claim 2 wherein each of the first grinding means and the second grinding means further comprises a plurality of grinding wheels mounted respectively to a plurality of grinder motors disposed successively along the conveyor, the grinding wheels being disposed with respect to the conveyor such that the grinding wheels will contact the edge of the workpiece. 
     
     
       4. The apparatus of claim 3 further comprising means for spraying a coolant at the surface where the grinding wheels contact the workpiece. 
     
     
       5. The apparatus of claim 2 wherein each of the first and second polishing means further comprises a plurality of polishing wheels mounted respectively to a plurality of polishing motors disposed successively along the conveyor, the polishing wheels being positioned with respect to the conveyor such that the polishing wheels will contact the workpiece along a ground edge. 
     
     
       6. The apparatus of claim 5 wherein each of the first polishing means and the second pair of polishers further comprises a means for spraying a polishing medium onto the surface where the polishing wheels contact the workpiece. 
     
     
       7. The apparatus of claim 5 wherein each of said polishing motors further comprises an ammeter for measuring the load on the polishing motor. 
     
     
       8. The apparatus of claim 2 wherein the conveyor further comprises horizontal support rollers for guiding the workpiece through the apparatus and for preventing the workpiece from rotating as it passes through the first grinding means, the second grinding means, the first polishing means, and the second polishing means. 
     
     
       9. The apparatus of claim 8 wherein the conveyor means further comprises means for pressing the workpiece down into firm contact with the conveyor while the workpiece is being ground and polished. 
     
     
       10. The apparatus of claim 2 wherein the turntable further comprises: a means for sensing the arrival of a workpiece at the turntable;   a lifting piston responsive to the means for sensing for lifting the workpiece from the conveyor when the workpiece is in position over the lifting piston;   first means for determining when the workpiece has been lifted;   a rotation pad disposed above the lifting piston such that when the lifting piston lifts the workpiece, the workpiece comes into contact with the rotation pad;   a rotation piston for turning the rotation pad through a specified angle when the workpiece is in contact with the rotation pad;   second means for determining when the rotation piston has finished rotating the rotation pad and thereupon causing the lifting piston to lower the workpiece back into contact with the conveyor.   
     
     
       11. The apparatus claimed in claim 10 wherein the rotation piston is a double-acting piston responsive to the position of the lifting piston, whereby when the workpiece has been returned to the conveyor, the rotation piston is returned to its initial position. 
     
     
       12. An apparatus for grinding the edges of a workpiece having at least two pairs of opposing sides comprising: a conveyor for transporting the workpiece through a series of sequential work stations;   first work station means for grinding the edges of a first pair of opposing sides of the workpiece positioned in the general direction in which the workpiece is transported;   first rotating means for rotating the workpiece independent of the conveyor to position a second pair of opposing sides in the general direction in which the workpiece is transported and comprising a turntable;   second work station means for grinding the edges of the second pair of opposing sides;   third work station means for polishing the edges of the second pair of opposing sides;   second rotating means for rotating the workpiece separately from the conveyor to position the first pair of opposing sides in the general direction in which the workpiece is transported and comprising a turntable; and   fourth work station means for polishing the edges of the first pair of opposing sides.   
     
     
       13. An apparatus for grinding the edges of a workpiece having at least two pairs of opposing sides comprising: a conveyor for transporting the workpiece through a series of sequential work stations;   first work station means for grinding and polishing the edges of a first pair of opposing sides of the workpiece positioned in the general direction in which the workpiece is transported;   rotating means for rotating the workpiece independent of the conveyor to position a second pair of opposing sides in the general direction in which the workpiece is transported and comprising a turntable; and   second work station means for grinding and polishing the edges of said second pair of opposing sides.   
     
     
       14. An apparatus for grinding the edges of a workpiece having at least two pairs of opposing sides comprising: a conveyor for transporting the workpiece through a series of sequential work stations;   first work station means for grinding the edges of a first pair of opposing sides of the workpiece positioned in the general direction in which the workpiece is transported;   first rotating means for rotating the workpiece independent of the conveyor to position a second pair of opposing sides in the general direction in which the workpiece is transported and comprising a turntable;   second work station means for grinding the edges of a second pair of opposing sides of the workpiece positioned in the general direction in which the workpiece is transported;   second rotating means for rotating the workpiece independent of the conveyor to position said first pair of opposing sides in the general direction in which the workpiece is transported and comprising a turntable;   third work station means for polishing the edges of said first pair of opposing sides;   third rotating means for rotating the workpiece independent of the conveyor to position said second pair of opposing sides in the general direction in which the workpiece is transported and comprising a turntable; and   fourth work station means for polishing the edges of the second pair of opposing sides.   
     
     
       15. The apparatus of claim 12 or claim 13 or claim 14 wherein each grinding means further comprises a plurality of grinding wheels mounted respectively to a plurality of grinder motors disposed successively along the conveyor, the grinding wheels being disposed with respect to the conveyor such that the grinding wheels will contact the edge of the workpiece. 
     
     
       16. The apparatus of claim 12 or claim 13 or claim 14 wherein each of the polishing means further comprises a plurality of polishing wheels mounted respectively to a plurality of polishing motors disposed successively along the conveyor, the polishing wheels being positioned with respect to the conveyor such that the polishing wheels will contact the workpiece along a ground edge. 
     
     
       17. The apparatus of claim 16 wherein each of said polishing motors further comprises an ammeter for measuring the load on the polishing motor. 
     
     
       18. The apparatus of claim 12 or claim 13 or claim 14 wherein the turntable further comprises: a means for sensing the arrival of a workpiece at the turntable;   a lifting piston, responsive to the means for sensing, for lifting the workpiece from the conveyor when the workpiece is in position over the lifting piston;   means for determining when the workpiece has been lifted;   a rotation pad disposed above the lifting piston such that when the lifting piston lifts the workpiece, the workpiece comes into contact with the rotation pad;   a rotation piston for turning the rotation pad through a specified angle when the workpiece is in contact with the rotation pad; and   means for determining when the rotation piston has finished rotating the rotation pad and thereupon causing the lifting piston to lower the workpiece back into contact with the conveyor.   
     
     
       19. The apparatus claimed in claim 18 wherein the rotation piston is a double-acting piston responsive to the position of the lifting piston, whereby when the workpiece has been returned to the conveyor, the rotation piston is returned to its initial position. 
     
     
       20. An apparatus for grinding the edges of a workpiece having at least two pairs of parallel sides comprising: a conveyor for transporting the workpiece through a series of sequential work stations;   first work station means for grinding and polishing the edges of a first pair of parallel sides of the workpiece when positioned parallel to the direction in which the workpiece is transported;   means for lifting the workpiece from the conveyor, rotating the workpiece to position a second pair of parallel sides in a direction parallel to the direction in which the workpiece is transported, and lowering the workpiece back down to the conveyor; and   second work station means for grinding and polishing the edges of the second pair of parallel sides.   
     
     
       21. An apparatus for grinding the edges of a workpiece having at least two pairs of parallel sides comprising: a conveyor for transporting the workpiece through a series of sequential work stations;   first work station means for grinding the edges of a first pair of parallel sides of the workpiece when positioned parallel to the direction in which the workpiece is transported;   first means for lifting the workpiece from the conveyor, rotating the workpiece to position the second pair of parallel sides in a direction parallel to the direction in which the workpiece is transported, and lowering the workpiece back down to the conveyor;   second work station means for grinding the edges of the second pair of parallel sides;   second means for lifting the workpiece from the conveyor, rotating the workpiece to position the first pair of parallel sides in a direction parallel to the direction in which the workpiece is transported, and lowering the workpiece back down to the conveyor;   third work station means for polishing the edges of the first pair of parallel sides;   third means for lifting the workpiece from the conveyor, rotating the workpiece to position the second pair of parallel sides in a direction parallel to the direction in which the workpiece is transported, and lowering the workpiece back down to the conveyor; and   fourth work station means for polishing the edges of the second pair of parallel sides.   
     
     
       22. An apparatus for grinding the edges of a workpiece having at least two pairs of opposing sides comprising: a conveyor for transporting the workpiece through the apparatus;   first grinding means for grinding a first pair of opposing sides of the workpiece;   first rotating means for rotating the workpiece through a specified angle, said rotating means comprising a means for sensing the arrival of a workpiece at the rotating means; a lifting piston, responsive to the means for sensing, for lifting the workpiece from the conveyor when the workpiece is in position over the lifting piston; means for determining when the workpiece has been lifted; a rotation pad disposed above the lifting piston such that when the lifting piston lifts the workpiece, the workpiece comes into contact with the rotation pad; a rotation piston for turning the rotation pad through a specified angle when the workpiece is in contact with the rotation pad; and means for determining when the rotation piston has finished rotating the rotation pad and thereupon causing the lifting piston to lower the workpiece back into contact with the conveyor;   second grinding means for grinding a second pair of opposing sides of the workpiece;   first polishing means for polishing the second pair of opposing sides of the workpiece;   second rotating means for rotating the workpiece through a specified angle, said rotating means comprising a means for sensing the arrival of a workpiece at the rotating means; a lifting piston, responsive to the means for sensing, for lifting the workpiece from the conveyor when the workpiece is in position over the lifting piston; means for determining when the workpiece has been lifted; a rotation pad disposed above the lifting piston such that when the lifting piston lifts the workpiece, the workpiece comes into contact with the rotation pad; a rotation piston for turning the rotation pad through a specified angle when the workpiece is in contact with the rotation pad; and means for determining when the rotation piston has finished rotating the rotation pad and thereupon causing the lifting piston to lower the workpiece back into contact with the conveyor; and   second polishing means for polishing the first pair of opposing sides of the workpiece.   
     
     
       23. An apparatus for grinding the edges of a workpiece having at least two pairs of opposing sides comprising: a conveyor for transporting the workpiece through the apparatus;   first grinding means for grinding a first pair of opposing sides of the workpiece;   first polishing means for polishing the first pair of opposing sides of the workpiece;   first rotating means for rotating the workpiece through a specified angle, said rotating means comprising a means for sensing the arrival of a workpiece at the rotating means; a lifting piston, responsive to the means for sensing, for lifting the workpiece from the conveyor when the workpiece is in position over the lifting piston; means for determining when the workpiece has been lifted; a rotation pad disposed above the lifting piston such that when the lifting piston lifts the workpiece, the workpiece comes into contact with the rotation pad; a rotation piston for turning the rotation pad through a specified angle when the workpiece is in contact with the rotation pad; and means for determining when the rotation piston has finished rotating the rotation pad and thereupon causing the lifting piston to lower the workpiece back into contact with the conveyor;   second grinding means for grinding a second pair of opposing sides of the workpiece; and   second polishing means for polishing the first pair of opposing sides of the workpiece.   
     
     
       24. An apparatus for grinding the edges of a workpiece having at least two pairs of opposing sides comprising: a conveyor for transporting the workpiece through the apparatus;   first grinding means for grinding a first pair of opposing sides of the workpiece;   first rotating means for rotating the workpiece through a specified angle, said rotating means comprising a means for sensing the arrival of a workpiece at the rotating means; a lifting piston, responsive to the means for sensing, for lifting the workpiece from the conveyor when the workpiece is in position over the lifting piston; means for determining when the workpiece has been lifted; a rotation pad disposed above the lifting piston such that when the lifting piston lifts the workpiece, the workpiece comes into contact with the rotation pad; a rotation piston for turning the rotation pad through a specified angle when the workpiece is in contact with the rotation pad; and means for determining when the rotation piston has finished rotating the rotation pad and thereupon causing the lifting piston to lower the workpiece back into contact with the conveyor;   second grinding means for grinding a second pair of opposing sides of the workpiece;   second rotating means for rotating the workpiece through a specified angle, said rotating means comprising a means for sensing the arrival of a workpiece at the rotating means; a lifting piston, responsive to the means for sensing, for lifting the workpiece from the conveyor when the workpiece is in position over the lifting position; means for determining when the workpiece has been lifted; a rotation pad disposed above the lifting piston such that when the lifting piston lifts the workpiece, the workpiece comes into contact with the rotation pad; a rotation piston for turning the rotation pad through a specified angle when the workpiece is in contact with the rotation pad; and means for determining when the rotation piston has finished rotating the rotation pad and thereupon causing the lifting piston to lower the workpiece back into contact with the conveyor;   first polishing means for polishing the first pair of opposing sides of the workpiece;   third rotating means for rotating the workpiece through a specified angle, said rotating means comprising a means for sensing the arrival of a workpiece at the rotating means; a lifting piston, responsive to the means for sensing, for lifting the workpiece from the conveyor when the workpiece is in position over the lifting piston; means for determining when the workpiece has been lifted; a rotation pad disposed above the lifting piston such that when the lifting piston lifts the workpiece, the workpiece comes into contact with the rotation pad; a rotation piston for turning the rotation pad through a specified angle when the workpiece is in contact with the rotation pad; and means for determining when the rotation piston has finished rotating the rotation pad and thereupon causing the lifting piston to lower the workpiece back into contact with the conveyor; and   second polishing means for polishing the second pair of opposing sides of the workpiece.